As the electronic intelligence technology develops, various wearable devices emerge in succession, such as smart wristbands, smart watches and smart glasses. With the increase of market demands, higher functional requirements are set for the wearable devices. It is necessary to develop functions of wearable devices.
Current smart wearable devices can measure biological features of humans, for example, measure humans' heart rates and blood pressure. The functions of these smart wearable devices, however, are only limited to the measurement of biological features and unable to provide urgent solutions when people feel uncomfortable, so these smart wearable devices cannot meet the requirements when people are in urgent need of first-aid services.